Saw-grinder combination for thin rock section machines

ABSTRACT

A combination sawing and grinding instrumentality supported on a single arbor for the cutting and grinding of specimens into thin sections for microscopic analysis. An abrasive periphery of the saw is supported against dishing during cutting operations by cooperating plate and grinder means oppositely disposed on the blade. Importantly, the offset grinder means additionally serves to abrade the specimen to the required 30 micron thickness all in one operation without the use of a separate machine and without re-mounting of the slide mounted specimen.

United States Patent 11 1 1111 3,753,430

Oas Aug. 21, 1973 [54] SAW-GRINDER COMBINATION FOR THIN 3,127,887 4/1964Metzger 51/206 R X C SECTION MACHINES 635,753 10/1899 Diaz 51/206 R X[76] Inventor: ggilOas, Rt. 2, Box 133, Springfield, Primary ExaminerDonald G. Kelly Attorney-James D. Givnan, Jr. [22] Filed: June 14, 197221 Appl. No.: 262,695 ABSTRACT A combination sawing and grindinginstrumentality 52] Cl 1 25/14 51/207 51/209 R supported on a singlearbor for the cutting and grinding 25/15 of specimens into thin sectionsfor microscopic analy- [51] Int. Cl B24d-7/18 An r i e periphery of thesaw is supported [58] Field of Search...... 51/206 R 206 NF againstdishing during cutting by ing plate and grinder means oppositelydisposed on the blade. importantly, the offset grinder meansadditionally serves to abrade the specimen to the required 30 51/206 P,207, 209 R, 209 DL; 125/13-15 [56] References Cited micron thickness allin one operation without the s u e UNITED STATES PATENTS of a separatemachine and without re-mounting' of the 3,289,663 12/1966 Cary 125 13slide mounted Specimen 2,743,717 5/1956 Wilkin 125/13 3,556,073 1/1971Garrison 125/14 8 Claims, 6 Drawing Figures E f w FE L2 5 PATENTEI]M1921 I975 SHEET 1l1F2 22 THIN SECTION SAW-GRINDER COMBINATION FORTI'IIN ROCK SECTION MACHINES BACKGROUND OF THE INVENTION The presentinvention is embodied within a discoidal structure for mounting on a sawarbor or spindle for the dual function of cutting a rock specimen andgrinding same to a reduced thickness providing a very thin rock sectionof the type suitable for microscopic analysis.

In the field of petrography it is common practice to microscopicallyinspect a very thin, light transmitting section of rock mounted on aslide using both reflected and transmitted light techniques. Study ofthe thin rock section under a polarizing microscope enables coloridentification of the mineral constituency of the rock. The cutting ofthin rock sections for such analysis requires extreme precision asvariance from a desired thickness will render color indication of therock constituents extremely difficult. Ideally said rock sections are ofa uniform thickness of 30 microns (0.03 mm) for microscopic study.

Typically, such thin rock sections are formed by the cementing of asawed rock chip, one-quarter inch thick or so, on a glass slide with theslide in turn being mounted on a thin section cut-off saw machine forresectioning of the rock component to an approximate thickness of 0.380mm. The glass slide with the resectioned rock specimen in place thereonis then typically removed from the saw and mounted on a thin sectiongrinding machine for grinding to the desired thickness of 30 microns.

Various machines are available for performing these sawing and grindingoperations including those machines which perform both sawing andgrinding operations utilizing a single power source which drives at itsopposite ends the individual cut-off blade and grinding wheel. Suchmachines require remounting of the specimen, and are quite costly byreason of their size and their precise nature in view of the stringentsawing and grinding requirements. In some instances such machinesinclude screw feeds for advancing a rock section against the saw orgrinding wheel adding to their cost.

In presently known cut-off and grinding machines, of which i am aware,the slide bearing the rock specimen must be installed at least twice,once for specimen passage past the cut-off saw and again for thegrinding operation for reduction of the specimen to the 30 micronthickness. The double mounting effort in combination with differentmachine slide supporting arms or the like increases the likelihood of anon-constant thickness.

The circular blades used in thin section or cut-off machines are one ofseveral types of blades known in the art as diamond blades and includethose termed notched" blades, continuous rim blades and segmented bladesall having diamond particles secured about their perimeters by bondingmatrixes termed resinoid, metal and vitrified. Such blades are usuallyof relatively thin metal and hence are susceptible to dishing ordeflection when the rock specimen is advanced at other than a very slowrate. The dishing of a blade results in the sawed rock section having anon-constant thickness and accordingly, sawed sections sewn on presentthin section cut-off saws must be of excessive thickness to insure atleast a minimum thickness of the desired 30 microns. Obviously, thecloser the sawn section may be to the 30 micron thickness the lessgrinding will be necessary and loss of the specimen material.

Blade diameters commonly range from 6 inches on up to 24 and 36 inchdiameters with some cut-off machine blades being stabilized by some sortof blade guidance bearing against the blade sides adjacent the blade pe-SUMMARY OF THE INVENTION The present invention is embodied within apower driven instrumentality mounted on a single arbor bearing bothrigid cutting and grinding surfaces for the accurate forming of thinsections of rock or other specimens for later microscopic analysis.While the present invention is described with reference to petrographyother uses for such a device will become readily apparent to thoseskilled in the arts of dentistry, orthopedics, electronics and biologyto name a few where micro scopic analysis of extremely thin material isroutinely performed.

The circular saw-grinder structure shown and described includes a bladecomponent about the periphcry of which, and in common with known likecut-off saw blades, is of the diamond abrasive type which may be appliedin the course of blade manufacture in a variety of known methods. Theinstant invention is not limited to one particular style of abrasiveattachment but rather may utilize at its periphery any one of theavailable blade-abrasive cominations e.g., continuous rim, segmentedrim, notched rim and bonding matrixes.

inwardly spaced from the abrasive periphery of the structure aregrinding means disposed so as to progressively engage the rock specimenwith the cutting and grinding being performed with but one machine andwith but one installation of the slide mounted specimen thereon.Heretofore, at least two distinct operations were-necessary with twomountings most usually on individual sawing and grinding machines.

The blade and grinding components of the instant invention, in additionto expediting the forming of thin rock sections, cooperate to overcomethe problem of dishing or deflection of the blade during cutting. in aconventional circular saw the blade is reinforced against dishing bysmaller diameter plates or flanges, ordinarily one fourth of the bladediameter. The effectiveness of such plates is reduced by reason of theirnecessarily small diameter such being necessary in order that the bladehave a clean, largely unobstructed side surface passing in an arethrough the material. in the present structure the grinding means, inaddition to importantly grinding the specimen, contributes to bladestability. Said grinding means, in conjunction with an oppositelydisposed plate, reduces saw dishing to a neglible degree.

BRIEF DESCRIPTION OF THE DRAWINGS With attention to the accompanyingdrawings:

FIG. 1 is a side elevational view of a machine for forming thin rocksections equipped with a saw-grinder combination structure embodying oneform of theinstant invention,

FIG. 2 is a vertical section view taken along line 22 of FIG. 1 showingthe saw-grinder structure of the instant invention,

FIG. 3 is a sectional view of the saw-grinder combination taken alongline 3-3 of FIG. 2,

FIG. 4 is a schematic showing in edge elevation a glass slide with arock specimen, cemented thereon, part way through a grinding operationwherein approximately one-half of the rock section has been reduced to athin section,

FIG. 5 is a composite perspective view, from left to right, of a slidemounted rock chip, a sawn rock section and the finished thin section,and

FIG. 6 is a composite view of modified forms of sawgrinder combinationsin accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With continuing reference tothe accompanying drawing wherein applied reference numerals indicateparts similarly identified in the following specification, the referencenumeral 10 indicates generally the sawgrinder structure mounted forpowered rotation on an arbor 11.

A typical saw machine includes an electric motor 12 mounted by means ofits base 13 to a machine base B on which is also mounted an arborbearing support at 15. For the purpose of holdinga conventional slidemounted rock specimen for presentation to the sawgrinder combination anarm at 16 is journalled for both arcuate and longitudinal travel willrespect to a supporting bar 17. An exemplary arrangement forlongitudinally advancing arm 16 is disclosed in the form of a knurledwheel 18 with advancing movement of the arm being against a compressionspring 20 retained at its opposite end by a stop 21. The arm 16terminates downwardly in a boss 16A corresponding to the outsidediameter of bar 17 for precise pivoted movement about the axis of thelatter during a cutting and grinding operation against the motor drivensaw-grinder structure 10.

The arm 16 is adapted to mount a glass slide 22 for movement in a planeparallel to a plane containing the saw-grinder structure 10. Adjustablemeans 23 on the arm enable the plate to be temporarily secured within arecessed area in the arm. Typically, plate mounting structure onexisting machines provides for the temporary mounting of various sizedglass slides such structure not being important to an understanding ofthe present invention no further description of same is believednecessary. The structure above described is not dissimilar to that foundin existing cut-off saws and thin section grinders.

With particular attention to FIGS. 2 and 3 wherein one form of thepresent invention is shown, a circular blade component is indicated at24 having a peripheral rim portion 25 of diamond particles held within amatrix for cutting of the specimen by abrading. As earlier noted avariety of edge styles is provided by different blade manufacturers forthe securement of the diamond particles to the blades peripheral marginall being suitable for such use in the present structure. Bladethicknesses, while not important to the present invention, may rangefrom approximately 0.030 to 0.060 of an inch increasing with bladediameter.

Located on the arbor side of blade 24 are circular plate means 26 whichis apertured at its center at 26A for reception of the reduced end ofarbor 11. A central recessed area 27 of the platereceives a washer andnut combination at 28. Blade 24 is accordingly reinforced on its arborside against dishing (deflection).

Oppositely disposed from plate means 26 on blade 24 and inwardly spacedfrom blade edge 25 are grinder means 29. A peripheral marginal edge 30of the grinder means is contiguous with blade 24 and embodies diamondparticles suitable bonded to the main discoid portion 29 of the grinderin a manner not unlike that earlier mentioned for blade 24. Peripheralmarginal edge 30 embodies a first abrading surface 30A and a secondabrading surface at 30B operable respectively to reduce the rock sectionby grinding along perpendicularly related surfaces. A series ofequidistant pins 32 extend through corresponding apertures in blade 24terminating within aligned openings 32 formed in plate 26. Removableattachment means are indicated at 33 in the form of flat head threadedfasteners in counter sunk engagement with circular portion 29 of thegrinder which removal permits separation of the saw and grindercomponents for replacement or servicing purposes. Altematively,thegrinder means 29 may be removed, reversed and re-applied to the blade24. The fasteners 33 are inset somewhat from the surface of grinder body29 so as not to be exposed even after war has occurred thereon.

With attention to FIG. 4, a thin section is shown partially formed bythepassage of grinder edge 30 approximately halfway through the slidemounted specimen S. The peripheral surface 30A of grinder edge 30provides a first grinding surface which, ineffect, performs a stepgrinding operation on the specimen as seen in FIG. 4 with subsequentgrinding action (in the nature of a lapping operation) beingaccomplishedby the marginal surface 30B extending immediately inwardfromsaid edge.

Additionally, the grinder means 29 provides an additional function ofrigidity supporting juxtaposed rotating blade 24 to support same againstdishing during cutting.

With attention being directed to FIG. 6 wherein modified forms ofsaw-grinder structures are indicated generally at 40, 50, 60 and 70, thefirst modification at 40 comprises a saw blade 41 having a diamond edge42 of the general type earlier described. Secured as by an annular weld43A to the outer surface of blade 41 is a grinder core 43 of annularconfiguration. Fused to core 43 are diamond particles held in place by asuitable matrix 44 and providing a first grinding surface 44A. A surfaceat 448 constitutes a secondary grinding surface. In similarity to thefirst described embodiment a plate 45 is apertured at 46 to receive theend of a spindle 47 with a nut element 48 affixed to the spindle end andbearing against the apertured blade 41 to confine same and plate 45 inplace on the reduced and of the spindle. In this embodiment of theinvention the working surface of the grinder may be refurbished as maythe cutting edge 42 of the saw blade.

The modification indicated generally at 50 includes a saw blade at 51with a diamond particle abrasive periphery 52, the blade including athickened central portion or base 53 on and about which is fused adiamond embedded matrix 54 having a first grinding edge 54A and asecondary grinding surface at 543. Again perpendicular, contiguousworking surfaces are provided for step like grinding of the previouslycut rock specimen. A plate at 55 serves to reinforce blade 51 againstdeflection as in the earlier forms of the invention and in continuingsimilarity is centrally apertured at 56 for spindle attachment withretention thereon being by nut element 58 on the spindle end 57.

Indicated at 60 is yet another modified form of the invention comprisinga blade 61, having a cutting edge 62, the blade being of ring-likeconfiguration brazed or otherwise suitably secured at 63 along its innerdiameter to a plate 64. A diamond bearing matrix 65 provides a firstgrinding surface at 65A and is secured as by fusing to a shouldered,irregular surface 66 of plate 64. A secondary grinding surface isindicated at 65B. A nut element 67 received within a central recess 63Aof the plate retains same on a spindle end 68.

Indicated generally at 70 is still another form of the instant inventionwherein a balde 71, having a diamond cutting edge 72, is of annularconfiguration for placement about a plate member 73. A blade retainerring at 74 is secured at intervals to plate 73 by means of threadedfastners 75 with the fasteners and ring being removable from plate 73 topermit axial removal of blade 71. Studs, one of which is indicated at74A project inwardly from the inner surface of ring 74 for keyedengagement with openings 71A in the blade. Grinding means is embodiedwithin a diamond supporting matrix at 76 having a peripheral edge 76Awhich extends outwardly beyond its supporting plate 73 with a secondarygrinding surface indicated at 76B. Plate 73 is recessed at 73A for thepurpose of receiving a nut element 78 retaining the saw-grinderstructure on a spindle end 79.

While I have shown and described but a few embodiments of the inventionit will be apparent to those skilled in the art that the invention maybe embodied still otherwise without departing from the spirit and scopeof the invention.

Having thus described the invention what is desired to be secured undera Letters Patent is:

l. A combination saw-grinder structure for attachment to one end of asaw arbor for sequential cutting and grinding of a specimen into a thinsection during unidirectional closing movement of the specimen with saidstructure for later microscopic analysis, said sawgrinder structurecomprising,

a circular blade,

grinder means centrally mounted on said blade and spaced inwardly fromthe blade cutting edge, said grinding means including a first abradingsurface embodied within a peripheral wall contiguous with one sidewallof the blade, a second abrading surface normal to said first abradingsurface extending radially inward from said first abrading surfacewhereby upon closing movement of the sawgrinder structure and thespecimen the latter is initially sawn by the blade to a desiredthickness with subsequent grinding of the specimen to the desired thinsection thickness by said first and second abrading surfaces all beingaccomplished in one pass of the specimen past the saw-grinder structure.

2. The combination saw-grinder structure as claimed in claim 1additionally including plate means of lesser diameter than said bladeand carried by the saw arbor, said plate means serving to support saidblade and abrading surfaces against deflection during sawing andgrinding operations.

3. The combination saw-grinder structure as claimed in claim 2additionally including fasteners interconnecting the grinder means andsaid blade removably mounting said grinder means to said bladepermitting detachment for repair and replacement purposes or reversal ofsaid grinder means.

4. The combination saw-grinder structure as claimed in claim 2additionally including pins carried by said grinder means extendingthrough said blade and terminating within said plate means.

5. The combination saw-grinder structure as claimed in claim 2 whereinsaid grinder means additionally includes an annular core secured to saidblade.

6. The combination saw-grinder structure as claimed in claim 2 whereinsaid blade is formed with an annular central portion of greaterthickness than the adjacent blade portion, said annular central portionof the blade constituting a supporting base for said abrading surfaces.

7. The combination saw-grinder structure as claimed in claim 2 whereinsaid blade is of annular configuration, said plate being concentricallydisposed within said annular blade and secured thereto, said plateprojecting outwardly past one side of the blade to thereat support saidfirst and second abrading surfaces.

8. The combination saw-grinder structure as claimed in claim 2 whereinsaid blade is of annular configuration circumposed about said plate,said saw-grinder structure additionally including a blade retainer alsocircumposed about said plate, means removably mounting said retainer tosaid plate permitting blade removal, said plate projecting outwardlypast one side of the blade to thereat support said first and secondgrinding surfaces.

1. A combination saw-grinder structure for attachment to one end of asaw arbor for sequential cutting and grinding of a specimen into a thinsection during unidirectional closing movement of the specimen with saidstructure for later microscopic analysis, said saw-grinder structurecomprising, a circular blade, grinder means centrally mounted on saidblade and spaced inwardly from the blade cutting edge, said grindingmeans including a first abrading surface embodied within a peripheralwall contiguous with one sidewall of the blade, a second abradingsurface normal to said first abrading surface extending radially inwardfrom said first abrading surface whereby upon closing movement of thesaw-grinder structure and the specimen the latter is initially sawn bythe blade to a desired thickness with subsequent grinding of thespecimen to the desired thin section thickness by said first and secondabrading surfaces all being accomplished in one pass of the specimenpast the saw-grinder structure.
 2. The combination saw-grinder structureas claimed in claim 1 additionally including plate means of lesserdiameter than said blade and carried by the saw arbor, said plate meansserving to support said blade and abrading surfaces against deflectionduring sawing and grinding operations.
 3. The combination saw-grinderstructure as claimed in claim 2 additionally including fastenersinterconnecting the grinder means and said blade removably mounting saidgrinder means to said blade permitting detachment for repair andreplacement purposes or reversal of said grinder means.
 4. Thecombination saw-grinder structure as claimed in claim 2 additionallyincluding pins carried by said grinder means extending through saidblade and terminating within said plate means.
 5. The combinationsaw-grinder structure as claimed in claim 2 wherein said grinder meansadditionally includes an annular core secured to said blade.
 6. Thecombination saw-grinder structure as claimed in claim 2 wherein saidblade is formed with an annular central portion of greater thicknessthan the adjacent blade portion, said annular central portion of theblade constituting a supporting base for said abrading surfaces.
 7. Thecombination saw-grinder structure as claimed in claim 2 wherein saidblade is of annular configuration, said plate being concentricallydisposed within said annular blade and secured thereto, said plateprojecting outwardly past one side of the blade to thereat support saidfirst and second abrading surfaces.
 8. The combination saw-grinderstructure as claimed in claim 2 wherein said blade is of annularconfiguration circumposed about said plate, said saw-grinder structureadditionally including a blade retainer also circumposed about saidplate, means removably mounting said retainer to said plate permittingblade removal, said plate projecting outwardly past one side of theblade to thereat support said first and second grinding surfaces.